This invention relates to a braking device for a focal plane shutter in a photographic camera.
For a braking device which prevents impact force, noise, and bouncing to occur in the shutter opening and closing members at the time of stoppage of the shutter release operation, there has so far been known such a device that absorbs the energy of motion in each of the shutter opening and closing members by means of a frictional brake. Such braking device, however, cannot again absorb the energy of motion, unless it is reinstated to its original position before the next shutter opening and closing operations take place. Hence, it has been the general practice to return the braking device to its original position at the time of shutter charging. This results in an increase in the load when shutter charging takes place.
On the other hand, when the members to be controlled by this frictional brake are used for turning-on of a synchro-switch (X contact), chattering of the synchro-switch caused by impact from collision of the two contacts of the switch can be prevented. Therefore, adoption of this system is most effective in flashing a speed light without failure and with exact timing. In this system, however, since the synchro-switch is kept turned on during a period of time from completion of the photographic operation to re-charging of the shutter, there may take place such a situation that a trigger capacitor for the speed light cannot be properly charged. In order to avoid such disadvantage, there has so far been known such a device, in which a switch to be turned on at the shutter release and turned off at the completion of the photographic operation (i.e., at the time of completion of the operation of the shutter opening and closing members) is connected in series with the synchro-switch. This switch is turned on and off in association with operation of the mirror system, or with the operation of the shutter release button. This device, however, is not also perfectly free from defect in that not only the number of switches to be provided increases by one, but also the speed light flashes simultaneously with turning-on of the switch on account of the floating capacitance of the wiring connection between the synchro-switch and the additional switch.